Molded boat hull



Nov. 11, 1952 iled Nov. 16, 1946 J. NEBESAR MOLDED BOAT HULL 1 2SHEETS-SHEET 1 INVEN TOR.

ROL Q TMNQLQW AT T ORNEYb NOV. 11, 1952 J NEBESAR 2,617,126

' MOLDED BOAT HULL iled NOV. 16, 1946 I 2 SHEETSSHEET 2 IN V EN TOR.

Q Robgri J-Nebesar P ATTORNEYS Patented Nov. 11 1952 UNITED STATESPATENT, OFF ICE MGLDED BOAT HULL Robert J. :Nebesa'r, Bristol, Va.,ass'ignor to Unijversal Moulded Products Corporation, Bristol, Va, acorporation of Delaware Application-November 16, 1946, Serial No.710,320

The object of my invention is to produce a one piece boat hull of anysuitable, and desirably highly compressible, fibrous material, but moreespecially a boat hull composed mainly of what is commercially known asimpregnated Fiberglas laminate.

One object of the invention is -.to effect the manufacture of the boathull at the least possible expense, particularly so far as concernslabor cost. Another object of the invention is to produce a boat thatwill not be affected by weather conditions, that will develop no cracksor leaks that will require calking, that may be of any desired coloralthough not required to be painted,

and that will not deteriorate with passage of time regardless of howfrequently it may be in actual use.

While my improved boat has characteristics which make it a new orimproved article of manufacture, the process of produoingitis of a highdegree of importance. The invention, therefore, involves a new andimproved process as we'll as a new construction of boat.

In the drawings:

Figs. 1, 3 and 4 are perspective views of the mandrel and otherelements, showing progressive stages in the manufacture of th'eboathull.

Fig. 2 is a cross-section on the "line 2-2 of Fig. 1.

Fig. 5 is a cross-section on the line -.5-5 of Fig. 4. 7

Fig. 6-is anenlarged section-on the line 6-6 of Fig.5. I

The mandrel a is a female mold having the contour of the boat hull tobemolded, -.but of slightly greater length at stem end. The @mandrel isof polished castiron or aluminum alloy or other metal of sufficientthickness and rigidity to resist distortion if subjected to unbalancedfluid pressure. It is substantially thicker along the bottom than alongits side and is provided with feet I), which not only support, but alsoreinforce, the mandrel. Around its upper edge the mandrel is providedwith an outwardly projecting flange c, to which are secured hingedclamps d.

In the stern end of the mandrel is inserted one or more sectional castiron or other metal end plates e which are virtually elements of themold and impart a substantially greater thickness to the mold at thisend, their main purpose, however, being to provide a removable moldelement which, at the conclusion of the molding and after cure, isslipped out, leaving some clearance at the transom of the hull and. thetransom end of 1 Claim. (01. 9-6,)

2 the mandrel proper to facilitate removal .of the molded hull.

Inserted into a groove formed in the inner face of the bottom of themandrel along its longitudinal center is a strip '13, the upper face ofwhich is coated with a thermosetting resin and ultimately forms anintegral part, namely, the heel, of the hull. Inserted into a recess in.one of the .end plates 6 is a wooden board .or block 9 which is alsocoated on its innerface with a thermosetting resin and ultimately formsan integral part of the hull, namely, the motor clamp block.

Layers h of a suitable fibrous material, .preferably glass fibres formedinto sheets and known commercially as Fiberglas, are impregnated withthermosetting resin, .and are laid into the mandrel. There may be onelayer but preferably there are two or more layers. For example, twolayers are shown. They are laid into the mandrel in theform of widesheets. 'The sheets may have a fairly wide overlapalong the region ofthe keel, so as toimpart a greater thickness to the hull in a zone ofselected width along the keel region. Overlying this thicker zone ofFiberglas is a keel reinforcement 7c, which is covered with one or morelayers .(one is-shown) of Fiberglas.

In the transom also thereis-an added layer or layers of Fiberglas andconfined between layers is .atransom reinforcement m,,.preferably ofplywood.

The two layers of Fiberglas are spaced apart at their outer edges toreceive between them a wooden inwale reinforcement n. Or, alternatively,the inwale reinforcement may be confinedtbetween the .two layers .ofFiberglas and .an added layer or layers of Fiberglas.

'Thesekeel-, transom-, and inwale-reinforcements may all be resin-coatedbefore insertion between the layers of Fiberglas. They all ultimatelyform integral parts of the completed hull.

After the Fiberglas mat with its enveloped reinforcements just describedis laid into the hull certain wooden parts are applied to the inner faceof the mat; that is, the face oppositethat which contacts with the mold.These parts are the seat supporting blocks 0 (usually three on eachside) and the motor board 11. Before these elements are laid against theFiberglas they are coated on their inner face with thermosetting resinand are held in place by screws s which tap into, but do not extendcompletely through, the mandrel.

The inner (exposed) face of Fiberglas and the wood parts 0 and p arethen coated with thermosetting resin and covered with cellophane, V

A blanket r of flexible material, preferably of uncured rubber so as tobe elastic as well as flexible, is beforehand moulded in the mandrel inwhich all the protruding wood parts are located and held in place sothat when cured this material would have the shape of the inside of theboat with edges of the blanket 1' extending over the flange c of themandrel. In the moulding operation of the boat such blanket r is thenplaced over the mandrel into which all the elements, including theFiberglas mat with resin, are laid in, the edge of the blanket extendingover the flange c of the mandrel, and a steel clamping ring t havingapproximately the contour and dimensions of the flange c is laid overthe edge of the blanket r overlying the flange c and is secured in placeby the clamps d, the mould being thus made air-tight.

Vacuum pipes v are connected to and extend through the mandrel, and airconfined between the mandrel and the blanket is exhausted. The mold sideof the blanket is provided with a multitude of little depressions whichform a multitude of complementary projections on the inner face of themat. Thereby venting is facilitated.

The entire assembly is then rolled into an autoclave (not shown) whereinfluid pressure is applied by means of steam and air. During the cure thevacuum through line may be maintained, or the vacuum line may merelyfunction as a vent to discharge outside of the autoclave any vapor thatmay be created inside the mold during cure.

After cure the clamping ring t and the blanket 1' are removed, thefilling pieces 6 are slipped out, and the hull is removed. The edge ofthe hull is trimmed, preferably so as to cut through the inwalereinforcement.

By the described process, there is produced a smooth one-piece rigidhull, with all primary wood members securely bonded to, or sandwichedin, the impregnated Fiberglas laminate.

An important feature of the process is the molding of the rubberblanket, before application of fluid pressure, to the metal mold andparticularly to the wood parts assembled in it. This preliminary moldingof the rubber blanket is of importance, as otherwise the blanket, underfluid pressure, would not stretch sufficiently to make it closelyconform to these sharply projecting seat supporting blocks and motorboard and voids would be formed, thereby producing a defective hull.

Other important features of the process are: the reinforcement of theFiberglas mat by embedding therein the hull reinforcement, the tran somreinforcement and the inwale reinforcement,

and the application of the seat supporting blocks and motor board (andany other desired element) to the matall before the application ofvacuum, heat and fluid pressure. Fluid pressure is not mainly reliedupon to conform the mat and the attached parts to the mold, the mainfunction of the fluid pressure being to consolidate and densify theFiberglas so as to form a rigid hull. The sheets of Fiberglas mat arenot dense and when subjected to pneumatic pressure the mat is reduced inthickness to approximately 25 of its original thickness.

A one piece boat hull formed by the described process has maximumdurability. It is not adversely affected by heat or other weatherconditions. It develops no cracks or leaks that require calking. It doesnot require painting. A dye of any color may be mixed with thethermosetting resin and the plastic material impregnated with both; andthe completed boat will have the color of the dye, and the color willnot be superficial but will permeate the entire hull.

A very practical advantage is that the whole process may be performedexpeditiously by labor that is not highly skilled, the labor cost beinga decidedly minor factor of the total cost, which in turn is much belowthe cost of boats built by conventional methods.

What I claim and desire to protect by Letters Patent is:

A boat hull the main body of which consists of highly compressed anddensified layers of fibrous material having integrally united therewithon its outer face a keel and a motor clamp block and on its inner face aseat supporting block and a motor board and having confined betweenlayers of said fibrous material a keel reinforcement, a transomreinforcement and an inwale reinforcement.

ROBERT J. NEBESAR.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,776,790 Harvey et al. Sept. 30,1930 2,008,136 Gonyer July 16, 1935 2,276,004 Vidal et a1. 7 Mar. 10,1942 2,312,333 Gramelspacher Mar. 2, 1943 2,370,429 Vidal Feb. 27, 19452,376,753 Bowen May 22, 1945 2,417,586 Crosley Mar. 18, 1947

